When you look them up in the dictionary, you may find they both mean “to sleep”.
Yes, sometimes they can be interchangeable but while 寝る = ねる ( = neru) often means “to go to bed” ,“to intend to sleep consciously”,

眠る= ねむる ( = nemuru) means simply “to fall a sleep or “to fall asleep because you can’t help it or control it”

Here are more explanations and details:

寝る ( = neru)

* The movement of your body and mind temporarily slow down

* When you intend to sleep consciously

→Action of going to bed
→Action of going to sleep
→To lay down and sleep

* To be in a subconscious condition with your eyes closed.

The counterpart verb is:

起きる = おきる= okiru = to get up

眠る ( = nemuru)

* The movement of your body and mind temporarily slow down

* to fall asleep

* to imply deep sleep

* It refers to the condition of your body while it is sleeping — you don’t necessary need to lay down to fall asleep. (Ex. sitting down, standing up, etc.)

The counterpart verb is:

目を覚ます= me wo samasu = to be awake

************************************************★In some sentences, you will see both 寝る（ = neru) and 眠る ( = nemuru) :

You see the definition, the movement of you body and mind gets decreased tentatively for both 寝る( = neru) & 眠る ( = nemuru)

Ex. 「ああ、よく寝た。or よく眠れた。」

= Aa, yoku neta. or nemureta.

= Haaa I slept well (for a long time)! or I was able to sleep very well.

= I have been just eating and sleeping everyday. (That’s all I do in my life.)

*二度寝 = nidone

（verb二度寝する= nidone suru )

= to go back to sleep after waking up once

Like in English, 寝る ( = neru) also has a sexual connotation.

Ex.「もう彼女と寝たの？」

= Mou kanojo to netano?

= Did you sleep with her already?

*川の字になって寝る

= kawa no ji ni natte neru

= Three people sleep next to each other like a letter of川 ( = kawa)

Like this…

Note : In Japan, it is pretty common to sleep with your child in the same room when they are small.
So when three people (usually parents and a child) lined up (like a letter of 川 ( = kawa) we use this expression.

= My father always lies dozing (on the floor) in pajamas at home on Sundays.

*雑魚寝 = zakone = this describes many people sleep in a huddle, to sleep crowded together in the same room.

*寝不足 = nebusoku = lack of sleep

Ex.今日は寝不足だ。

= Kyou wa nebusoku da.

= I haven’t slept enough today.

********************************************

眠る = ねむる= nemuru

1) to fall asleep, to sleep

*最近よく眠れない。

= Saikin yoku nemurenai

= I haven’t been sleeping well lately

*眠りが浅い

= nemuri ga asai

= shallow sleep

*眠りが深い

= nemuri ga fukai

= deep sleep

*眠りから覚める

= nemuri kara sameru

= to be awake from one’s sleep

*眠りにつく

= nemuri ni tsuku

= to fall asleep

*深い眠り

= fukai nemuri

= a deep sleep

Ex. お姫様は深い眠りから覚めました。

= Ohimesama wa fukai nemuri kara samemashita.

= The princess awoke from a deep sleep.

The fairy tale that we all know is,

*眠れる森の美女

= Nemureru mori no bijo

= ”Sleeping Beauty”

2) 眠る ( = nemuru) also describe something is in the condition of not being used for a long time.

Ex, うちに使わずに眠っているピアノが一台ある。

= Uchi ni tsukawazu ni nemutte iru piano ga ichidai aru.

= In my house we have a piano that nobody has played for a long time.

3) 眠る ( = nemuru) is also a metaphor for passing away.

*永遠の眠りにつく

= eien no nemuri ni tsuku

= to sleep forever, to die

or
*永眠する
= eimin suru

4) Other expressions with 眠

*眠くなる

= nemuku naru

= to get sleepier, to feel sleepy

Ex. 眠くなってきた。

= nemutaku natte kita

= I’m getting sleepier

*眠たい

= nemutai

= to be sleepy

*眠い

= nemui

=to be sleepy

*居眠り

= inemuri

= a catnap, a snooze

*仮眠する

= kamin

= catnap,short sleep, to catch 40 winks

=to catch a little sleep/to catch some z’s

*快眠

= kaimin

= a good sleep

*不眠症

= fuminshou

= insomnia

Ex. 私、最近不眠症なんだ。

= Watashi saikin fuminshou nanda

= I have been suffering from insomnia, you know.

*眠気 = nemuke = sleepiness

Ex. 眠気覚ましにコーヒーを飲む

= nemuke zamashi ni kouhii wo nomu

= to have a cup of coffee to keep oneself awake

*睡眠

= suimin

= to sleep

* 睡眠時間が短い

= suimin jikan ga mijikai

= to have a short sleep time, to not have much time to sleep

*睡眠をとる

= suimin wo toru

= to have a sleep

*睡眠不足

= suimin busoku

= a lack of sleep

*ノンレム睡眠

= non remu suimin

= non-REM sleep (non-rapid eye movement sleep)

*睡眠時間

= suimin jikan

= sleeping hours

*睡眠薬

= suimin yaku

= sleeping tablets, pills

*睡魔が襲う

= suima ga osou

= to get sleepysuddenly

Ex. 急に睡魔が襲ってきた。

= Kyuuni suima ga osotte kita.

= to suddenly feel sleepy

*睡魔と戦う

= suima to tatakau

= to fight off sleep

*熟睡

= jukusui

= a dead sleep

*爆睡 (colloquial)

= bakusui

= a dead sleep

＊＊＊＊＊＊＊＊＊＊

Japanese is full of onomatopoetic words and there are a few words to describe how we sleep.

When you describe a baby who is sleeping well, we often use,

*すやすや

= suyasuya

Ex. すやすや眠っているね。

= Suyasuya nemutte irune.

( You can also use it for adults.)

to be fast asleep

*ぐっすり

= gusssuri

*ぐーぐー ／グーグ

= guuguu

*ぐーすか (casual, comical)

= guusuka

*うとうとする

= utouto suru

= to doze off, to nod off

Other sleep related words :

*寝床

= nedoko

= bed, place to sleep

*寝具 (formal)

= shingu

= bedding

*布団

= futon

( I think “futon” has become an international word now.)

Ex. 布団を敷く

= futon wo shiku

(In many areas, they say 布団をひく= futon wo hiku)

Cultural note : Unlike western beds, traditionally we put back 布団 ( = futon) in the morning in the closet called 押し入れ ( = oshiire) and take them out before you sleep. Thus we can use the bedroom space during the day.

If you turn nemuru on its side it looks like a bed and a sheet with a persons head touching the sheet and the body as it floats and the mountains in the back ground and left to right turning into hills and then to the winding river as if the person has returned to the earth and its nature and the physics of motion and the change from being to the condition of not being.

Hi:D
I’m a big anime fan. An from watching sub and dubbed anime a lot, I can pick up words that’s how I know some greetings. Etc..

I really liked your lessons.
Do you do voice lessons.. or anything else besides writing them down?
I was just wondering if you did other stuff besides, blogs, writing the words down etc. I pick up by hearing more then seeing. That’s why I’m curious to know :D

Hello, ChelseyBear!
I do Skype lesson only for certain people but not for public at the moment.
I sometimes give listening practice on Facebook or Twitter using a movie preview or anime. Will try to post the quiz on Maggie’s Room.

Hi I recently discovered your blog. It’s very informative and easy to understand but the Romaji is highly distracting. I suggest to start using Hiragana instead when explaining the pronounciation of the Kanji. Furthermore no Japanese person ever uses Romaji and it only serves as a factor to cripple early students who has yet to learn/write the kana. So please ditch the Romaji next time.

I greatly appreciate the romaji under the kanji. It helps me learn the kanji faster instead of switching between this page and many other websites to look up the meaning over and over again. Everything I need to learn these phrases is on one page. Thank you Maggie Sensei. Your website is thorough and fantastic